The leader of the cult accused of kidnapping a teenager refused to reveal yesterday where the boy is being held.

Bobby Kelly was made a ward of court earlier this week because of fears about his safety with members of the Jesus Christians. His whereabouts were still unknown last night and there was concern that the cult was trying to take him abroad.

Yesterday, as the hunt continued, the cult leader Dave McKay, who is based in Sydney, spoke exclusively to the Daily Express.

But he refused to say if his followers would surrender the youngster to the police and end the anguish of his family.

It was clear from an earlier e-mail from McKay that he had been in touch with the group. They are aware that Bobby, 16, is a ward of court and that they must not frustrate the efforts by police and court officials to find him.

But McKay would not give an assurance that Bobby's whereabouts would be revealed. When he was pressed to give an answer he hung up.

He said in his e-mail that Bobby had been staying with members of the Jesus Christians of his "own free will" and that his grandmother Ruth Kelly had been in "complete agreement".

Yesterday Mrs Kelly, 58, with whom he lived in Romford, Essex, was close to exhaustion because of the stress of the efforts to rescue Bobby.

He had stayed with her to finish his education at a local school when his mother, Jessica, moved to Clacton with her daughter Charlotte, five.

Yesterday, the two women were in tears as they spoke of their fears for Bobby whose ambition had been to be another Richard Branson.

Meanwhile, McKay tried to blame a friend of the family for the fuss.

He said: "It is our guess that there has been an over-reaction from his former youth pastor, based on religious differences and nothing more.

"We are confident that his action was not based on any genuine threat to his welfare."

David Whitehouse, the family friend who helped set up the rescue effort, angrily denied the accusation.

He said: "They represent themselves as Christians, but they wanted to spirit Bobby away from his family. That is not the teaching of Jesus."

Graham Baldwin, who runs Catalyst, a charity that helps families whose children have been taken over by cults, said yesterday: "We would like these people to be investigated because we think there are other young people who may have joined them and whose families are very worried."

Bobby was made a ward of court on Wednesday and the Official Solicitor Lawrence Oates was appointed as his guardian.

When the boy is found he will be taken before a High Court judge who will decide his future.

Bobby, who had just finished his GCSE exams at Redden Court School was out shopping with his grandmother when he met one of the cult's members handing out leaflets outside Marks & Spencer's in Romford. Later that day he announced he was joining them.

The Jesus Christians who are being sought by police are travelling in a white Daf Leyland van registration [EDIT].

The group includes an Australian couple and the woman is called Sue. She told Ruth Kelly that she was 33.

Bobby informed his grandmother that he was not allowed to speak to her unless Sue was present and she listens to the conversation when he has phoned home.Mr Justice Sumner, who made the "search and find" order on Bobby, was told the group had been planning to take him abroad and had tried to get documents that would help them get him a passport.